1. Field of the Invention
The present invention is generally related to a marine propulsion system that uses an in-line engine and, more particularly, to a system in which the in-line engine is tilted at a preselected angle from a generally vertical plane.
2. Description of the Prior Art
Marine propulsion systems use engines of various types. Inboard marine propulsion systems and sterndrive systems typically dispose the engine within the hull structure of a marine vessel. In most typical applications of internal combustion engines associated with inboard or sterndrive systems, the engine is aligned symmetrically relative to a generally vertical plane with its crankshaft disposed in parallel relation with a vertical plane that bisects the hull of the marine vessel in a direction extending from its bow to its stern. However, not all marine propulsion systems meet this description of the typical application.
U.S. Pat. No. 4,040,379, which issued to Betts on Aug. 9, 1977, describes a dual sterndrive mounting arrangement. A boat includes a boat hull having a centerline, a pair of sterndrive units supported by the boat hull and each including an engine. A shaft driven by the engine has an axis of rotation extending at an angle to the boat centerline so that the axes converge in a rearward direction, a propulsion unit disposed rearwardly of the engine and a propeller driven by the shaft. It also includes a unit supporting the propulsion unit for steering movement relative to the boat hull.
U.S. Pat. No. 4,940,436, which issued to Newman on Jul. 10, 1990, describes a marine engine system with inboard mounted engine and depending drive unit. A marine drive system includes one or more engines mounted inboard of a boat adjacent the boat transom. The engines are disposed such that their longitudinal axes are substantially perpendicular to the boat centerline and parallel to the boat transom. A drive unit extends substantially vertically relative to each engine during operation. The drive unit preferably includes a drive housing which is mounted to the boat so as to be pivotable between an operating position, in which the propeller is submerged, and an inoperative position in which the propeller is out of the water and the drive unit is disposed at an angle to the vertical relative to the engine. The construction provided by the engine is advantageously employed in a boat hull design in which a pocket is formed in the boat hull and a portion of the propeller path is disposed within the pocket. With the transverse placement of the engines, the pockets in the boat hull can extend from the front to the rear of the boat hull and do not require modification to accommodate placement of the engine.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
In certain boat applications, such as in conjunction with bass boats and other low profile marine vessels, the height of an engine positioned within the hull of the boat often obstructs valuable space in the rear part of the marine vessel. It would therefore be significantly beneficial if a marine propulsion system could be provided in which an engine can be located within the marine vessel, but without requiring the usual height clearance for the engine to be disposed within the marine vessel structure.